This invention relates to the performing of complex mechanical procedures, and, more particularly, to an approach for guiding a person or machine through those procedures.
Many modern systems are highly complex, both to construct and to repair. Manufacturers usually provide a maintenance manual for the systems, for the use of repair and maintenance personnel in the field. These maintenance manuals are highly comprehensive and include detailed, step-by-step procedures required to keep the system in normal operation through preventive maintenance and repair of failed portions of the system. For example, a typical military helicopter may have a maintenance manual that runs to over 50 volumes, has nearly 9,000 pages, and occupies over 15 feet of shelf space. Such masses of paper cannot be readily transported to many field sites where maintenance may be required.
The preparation of a maintenance manual of this size and complexity is itself a major undertaking. Updating the maintenance manual responsive to model revisions, new requirements, improved procedures, new capabilities and equipment add-ons, and the like is also highly time consuming. Once the manual is revised, the revisions must be made available to all field users.
The use of the maintenance manual is not simple in many cases. For most procedures, there are cross references to other sections of the manual, as well as to various supporting documents. As an example, if it is known that a particular piece of apparatus has failed, the mechanic does not simply open the manual to the section dealing with that apparatus and begin working. There are usually lists of preliminary tasks to be performed, such as taking necessary safety precautions, rendering the apparatus safe to work on, disassembling structure to reach the particular apparatus of interest, obtaining special parts or tools, obtaining consumables to be used in the procedure, etc. Upon reaching a particular step in the procedure, the mechanic may be referred to a supporting document for the instruction or information to perform some multistep action. After that referenced action is performed, the mechanic returns to the basic document and continues.
The most efficient way to present this information in a manual is with extensive cross referencing to other standard procedures, rather than placing every step of every procedure into one place. It has been estimated that a 9,000 page maintenance manual would grow to over 100,000 pages if every step of every procedure were written in order, without cross referencing. This amount of paper would be unacceptably large.
When confronted with this mass of information, it is possible for even the best mechanics to make mistakes or be inefficient. Typical mistakes include failing to take required safety precautions, turning to the wrong cross-referenced sections and beginning the wrong procedure, skipping entire procedures, skipping vital steps of the proper procedure, being confused by inconsistent wording in different procedures, and using the wrong parts, tools, or consumables. Typical inefficiencies include interrupting a procedure to locate a tool or consumable that was previously overlooked, starting over or retracing steps, having to sort through information that may be present in the manual but may not be needed for a particular procedure, and taking the time to complete necessary maintenance logs. These problems are of even more concern when the maintenance is performed in adverse conditions or by relatively inexperienced mechanics.
To overcome some of the problems inherent in the traditional approach to providing maintenance information, "paperless" maintenance systems have been developed. In such an approach, the entire maintenance manual is stored on a laser disk or other electronic medium that is used with a portable computer. The entire maintenance library thus weighs only a few pounds and can be readily transported. With good indexing, the mechanic can rapidly find a particular procedure to be performed and its related procedures as they are needed.
The existing paperless maintenance instruction systems still suffer from important shortcomings. They require the same time to write and prepare as traditional paper manuals. Updating with changes in procedures or models is slow and expensive. The mechanic can still make the same types of mistakes and have the same inefficiencies as discussed above.
There is a need for an improved approach to performing detailed mechanical tasks such as the maintenance of complex systems. Such an approach must permit the mechanic to work in an efficient, error-free manner, while reducing the cost and time required for writing and updating the manual. The present invention fulfills this need, and further provides related advantages.